In the electron microscope such as a transmission electron microscope (TEM), when observing a specimen, for example, since a tip part of a specimen holder (referred to as specimen cradle) to be inserted into the limited space between the gap of the objective pole piece for a transmission electron microscope is needed to insert into the limited space of the objective lens pole piece, and to be inclined to the electron beam optical axis in the specimen holder axis, inevitably, the specimen cradle is made as thin as possible.
For example, as the electron microscope will be described as an example of a transmission electron microscope, the specimen to be observed by a transmission electron microscope is observed by mounting it to the specimen cradle part. In order to fix and attach a TEM specimen mesh to the specimen cradle, the specimen cradle is required for at least the cradle base unit and a specimen holding member. Further, a specimen holding is required for any fixing means to sandwich a specimen mesh in the cradle body, therefore, a means arranging a screw for fixing is generally used.
Moreover, although and the thickness of the specimen holding plate, or the size of the screw for fixing a specimen are also a prerequisite in order to effectively utilize the limited space of the objective lens pole piece, but on humans handled, there is a limit to the miniaturization, in consideration of the durability of the screw itself, there is a limit to miniaturization. The screw on the M1˜M2 size at present is generally used.
Under such circumstances, as a method of exchanging a specimen, for example, a specimen exchange device made of a specimen chamber, a specimen-exchange chamber, a gate valve, a specimen exchange rod, is known (Patent Document 1).
Further, in recent years, a high resolution analysis of the electron microscope such as a transmission electron microscope (TEM: Transmission Electron Microscope), a scanning transmission electron microscopy: (STEM Scanning Transmission Electron Microscope) has advanced, for example, to the order from a nanometric to a picometric high-resolution analysis have been demanded. In a goniometer stage (Gonio) in the prior art, there is an opening and closing valve when inserting a specimen holder (Holder) from a spare chamber into a specimen chamber of a high vacuum (Patent Document 2).